The Connection: Vitamin D + Risk of Diabetes

By: Mark Lange, PhD

Despite nearly every cell and tissue having a vitamin D receptor, many in Western countries are deficient in this underrated vitamin. The impact of vitamin D deficiency is creeping into the spotlight due to the newfound links to a higher risk of several cancers, cardiovascular disease, bone fractures, and the metabolic syndrome.  With the also rising incidences of diabetes, researchers in Australia saw interesting results in a 12-year study on the link between the two.

The Study:

The 12-year study focused on a group of 903 healthy, Caucasian adults from a California suburb.  The subjects had their serum vitamin D levels measured during clinic visits from 1997 to 1999.  Then, the subjects had their vitamin D levels measured again in 2009, along with fasting plasma glucose and oral glucose tolerance. The researchers followed the cases until a diagnosis of pre-diabetes or diabetes, and they followed non-cases until their last test of 8-hour fasting plasma glucose


The Results:

Over the study period, 47 subjects developed diabetes and 337 became pre-diabetic.  The researchers determined that those with at least 30 nanograms per milliliter 25-hydroxyvitamin D in blood plasma did not become diabetic or pre-diabetic.  This is 10 ng/ml above the recommended 20 ng/ml 25-hydroxyvitamin D level recommended by the Institute of Medicine.

The authors state,

“We found that participants with blood levels of 25-hydroxyvitamin D that were above 20 ng/ml had one-third of the risk of diabetes and those with levels above 50 ng/ml had one-fifth of the risk of developing diabetes.”


What It Means:

The baseline measurements showed that the use of vitamin D and calcium supplements was lower in individuals who became diabetes cases than in those who did not, but only by a borderline trend.  Alcohol use, smoking, and self-reported regular strenuous exercise were not significantly associated with incidence of diabetes or pre-diabetes, so the authors recommend to reach 25-hydroxyvitamin D levels of 30 ng/ml, required dietary supplementation of 3,000 to 5,000 IU per da. They noted that you may get less if getting moderate daily sun exposure.




Park, S.K., et al.  Plasma 25-hydroxyvitamin D concentration and risk of type 2 diabetes and pre-diabetes: 12-year cohort study.  PLOS ONE 2018; 13(4): e0193070  DOI: 10/137/journal.pone.0193070